A direct role for AT1-aa in mediating hypertension during pregnancy via ET-1 was revealed following infusion of purified AT1-aa into pregnant rats from GD 12–19; this protocol increased renal levels of preproET-1 mRNA and MAP, and both of these responses were attenuated by oral administration of an ETA antagonist [161]. This evidence concerns the gene AGTR1 and hypertensive disorder.